Mantas, Angels and Kanaks: A New Caledonian Odyssey

“C’est bonne!” Our local guides, Pierre and Marino, flashed us two thumbs up as we emerged from the water after successfully deploying a custom Fastloc-GPS satellite tag on a male manta ray with a wingspan approaching ten feet. We had been diving the reefs of Ouvea for nearly a week, spotting mantas almost every day, but getting close enough underwater to attach a tag with our pole spears turned out to be more difficult than we expected.

Photo Credit: Shawn Heinrichs

Our team of Conservational International (CI) scientists had traveled thousands of miles to this remote atoll – a World Heritage Site and one of three provinces in the island nation of New Caledonia – in hopes of learning more about one of the South Pacific’s richest and most pristine marine habitats. As an avid diver myself, I have accompanied CI on previous expeditions to Indonesia and was sponsoring this particular expedition to New Caledonian. With my Brooks-Range brim hat, Down Sweater and All-in-One Map Tool in hand, I joined the CI team in researching and identifying a species off Ouvea in in the archipelago of New Caledonia.

The CI team was led by Mark Erdmann, who directs CI’s Asia Pacific Marine work from New Zealand; and included world renown ichthyologist Gerry Allen of Australia; Indonesian-based Sarah Lewis, a conservation biologist specializing in manta rays; Mael Imirizaldu, in charge of CI New Caledonia’s marine programs and our local guide; Schannel Van Dijken, marine program director for CI’s Pacific Islands program; and CI’s New Caledonia Country Director, Jean-Christophe Lefeuvre. For more than 20 years, Conservation International has utilized short, targeted expeditions to research the health of key ecosystems and assess the biological value of unexplored areas. The trip to Ouvea was one in a long tradition of ocean-based expeditions, touching four continents and every major ocean in the world, that have yielded critical information about some of the least understood places on Earth.

Along with sharks, sea turtles, and hundreds of reef fishes, the waters surrounding Ouvea are filled with manta rays, one of the oceans’ largest fish species. In many other areas of the Pacific manta populations are declining precipitously, harvested for their gill rakers, which, like shark fins, fetch hundreds of dollars a pound in Asian markets. But in Ouvea the local Kanak traditional communities or tribes that own and control the reefs consider the manta a sacred totem animal, and are working hard to protect the local population.

The Conservation International team based in New Caledonia invited us to Ouvea with a couple of key objectives in mind. First, they wanted to set up a manta ray research program in close coordination with the Kanak traditional communities. Our joint research into the mantas would start with photographing and cataloging mantas, followed by tagging several individual animals with small, lightweight satellite transmitters that would enable us to track movement and behaviors twenty-four hours a day over the course of several months, until the batteries died or the tag was dislodged. The local CI team also wanted us to document the extraordinarily rich and pristine reef system surrounding Ouvea, photographing and identifying as many different reef fish species as possible and building on a biodiversity survey of the region done some years ago by French scientists.

Thousands of individual mantas worldwide have already been identified and documented by conservation biologists at the Manta Trust, who created an on-line app where the collected information and photos could be shared and searched. Every manta has been identified with a name, number, and a photo showing the unique pattern of spots on their bellies, along with information about their size, sex, overall coloration, and condition, including scars or shark bites. More than a hundred mantas had already been spotted in New Caledonia; but we knew from our local guides that there were many more unidentified mantas in the Ouvea area. They described seeing up to seventy mantas in a single location, and felt confident that the local population would number in the hundreds.

We arrived just after Thanksgiving full of optimism, and in our first two days in Ouvea we spotted several mantas passing by, including several feeding on the surface and barrel rolling around the boat. Unfortunately, they always seemed to elude us – gliding away silently just as we entered the water with our snorkels or tanks — making it impossible to photograph them up close.

By the third day on the water, we devised a new plan to capture ID photos, setting up a stationary GoPro® camera underwater on the reef, programmed to take a photograph every second. We set the camera purposefully on top of a known manta cleaning station – a large coral outcrop where mantas come to be cleaned of parasites by wrasses and butterfly fishes – then left the area to search for mantas elsewhere.

The technique proved effective, and within a few days we managed to photograph eight individual mantas – one of which was a re-sighting of a previously known individual. Interestingly, we noted that many of the mantas had distinct bite-mark scars on their wings – the result of shark attacks. Also of interest was the number of all black mantas we encountered, far more than normally seen on reefs in the Indian Ocean and Southeast Asia, where the vast majority of mantas show a distinct “countershading” pattern of a black back and a white belly.

Despite the success with the photo ID’s, the mantas were still proving elusive in terms of tagging. On the sixth day, our luck changed. Almost immediately upon arriving at the cleaning station in the morning, a large male manta was spotted, calming circling the coral colony while being cleaned of parasites. He hardly took notice of us as we descended onto the reef with our tanks. As we settled in to watch, he decided to come and check us out, making several close passes and allowing us to obtain excellent ID photographs. He then went back to cleaning in front of us, allowing us to quickly deploy one of our satellite tags. Success!

Over the next few days, we had several close manta encounters, but unfortunately were not able to deploy any more tags. However, the one tag we did deploy began functioning brilliantly, revealing some interesting movements across the lagoon within the first 2 days of deployment.

The male manta at cleaning station, just before tagging.

While Sarah and Schannel focused primarily on the mantas, Matt and Mark split their time between the tagging effort and working alongside Gerry, combing each site inch by inch, taking hundreds of photos of reef fishes. Previous extensive surveys by both French and American colleagues in the region had identified nearly 700 species of reef fish from the Loyalty Islands (the offshore province of New Caledonia within which Ouvea is located), and the abundance of species here was astounding.

All of us immediately noticed the healthy shark populations of the atoll. Gray reef and whitetip reef sharks accompanied us on every dive (on one dive numbering close to 50 individuals), while silvertip, lemon, and zebra sharks made occasional appearances as well.

A zebra shark resting on the bottom.

Matt and Gerry identified a host of stunningly beautiful angelfish, which could be seen darting into crevices at every turn. Startled at first by the flash of the camera, they would soon habituate and emerge to allow themselves to be photographed. On one dive, we noticed an unusual red angel darting about within a dark cave. We managed one photograph before it disappeared, and were delighted to determine it is the rarely-seen Centropyge aurantia, a new record for New Caledonia.

On one of the first dives, we spotted a trio of fang blennies at the back of a cave that proved to be Meiacanthus ditrema – a species never before recorded in New Caledonia. More new records quickly followed, including the stunning fairy basslet Pseudanthias cooperi and the tiny dwarf goby Trimma xanthum. We also observed a number of other interesting fishes normally seen closer to the equator.

Our guide Marino also treated us to a rather incredible display of fish behavior with a clownfish he had befriended and trained while it was still young. Coaxing the clownfish out of its protective anemone, Marino had it perform acrobatic loops around his hands. When another diver tried the same thing, the clownfish darted away and headed straight back to Marino, showing a level of recognition and intelligence that surprised all of us, including Gerry, who authored the definitive book on the species and had never seen anything like it.

Three more exciting finds – the fang blenny Meiacanthus ditrema, the fairy basslet Pseudanthias cooperi, and the dwarfgoby Trimma xanthum – all new records for New Caledonia

In our final couple of days on site, we made a series of deeper (160-180 foot) dives to explore the caves below normal diving depths. Our efforts were handsomely rewarded with a pair of likely new species discoveries: a stunning dragonet in the genus Synchiropus and an unusual elongated dottyback with a bold racing stripe down the side. Clearly another series of deep dives in this region would yield many additional new discoveries. An excellent excuse for a follow-up expedition!

Two of the likely new species uncovered on our deeper excursions to 180 feet – a stunning Synchiropus dragonet, and an unusual elongate dottyback in the genus Lubbockichthys.

On our last night in Ouvea, our Kanak hosts treated us to a feast of local delicacies that included coconut crab, taro, and smoked fish. We set up a portable projector and took turns presenting our discoveries, including the many exciting new fish finds. All of us were delighted to see the first transmissions from the tagged manta, which showed that it had travelled a surprising distance across Ouvea lagoon.

Pierre and Marinot, who have been diving these waters since they were children, shared images and stories of their countless manta encounters, including one video featuring several mantas hovering almost motionless above a feeding station. If only we had been there with our tags!

We presented our hosts with a flash drive loaded with all of the images and videos we had collected on the expedition, and they reciprocated with a number of short videos they’ve taken over the past five years. Our plan now is to sit down with the Manta Trust and analyze the footage, undoubtedly identifying a large number of new photo records for the region that will be added to the online app.

The evening ended with plans for a follow-up expedition to deploy our remaining satellite tags sometime in the first half of 2016. Our guides Pierre and Marino also divulged that they have a number of secret spots where they reckon there are many new fish species awaiting discovery, and promised to take us there on the next trip.

A happy ending to an expedition that may have been frustrating at times, but was always interesting, and… in the end… highly productive. C’est bonne!